High frequency system



July 23,194& A. WIESSNER 2,298,917

HIGH FREQUENCY SYSTEM Filed April 13, 1938 Patented July 23, 1940 UNITEDSTATES HIGH FREQUENCY SYSTEM Alfred Wiessner, Berlin, Germany, assignorto C. Lorenz Aktiengesellschaft, Berlin-Tempelhof,

Germany, a company Application April 13, 1938, Serial No. 201,715 InGermany April 13, 1937 4 Claims.

The present invention relates to high frequency systems, and moreparticularly to selector rack arrangements in such systems as generallyemployed in telephone exchange stations.

It is well known to efiect intelligence transmission by means of highfrequency carrier currents, and to impress a plurality of carrier wavesupon the telephone lines in an exchange station. Systems of the abovementioned type require the provision of electric separating filterdevices so as to permit the high frequency and the low frequency messagecurrents to be impressed upon the transmission channel common thereto.It has been suggested in the past to employ specific racks adapted toreceive particular groups of electric separating filters, which consistof suitably interconnected capacities and inductances, but thisexpedient introduces certain disadvantages since it will be hardlypossible on account of the restricted space conditions inordinaryexchange offices to stow the great number of wires required forinterconnecting the lines and the electric filter devices.

The present invention has for its object to avoid the aforesaiddifficulties by arranging the filter devices directly in the selectorracks and in close proximity to the appertaining sets or groups ofselector switches and relays, so as to permit connecting wires of shortlengths to be used.

The invention will be more readily understood from the followingdescription taken in conjunction with the accompanying drawing, inwhich:

Fig. 1 is afront elevation of an arrangement according to the invention;Fig. 2 is a side elevation of the arrangement shown in Fig. 1; whileFig, 3 shows a suitable wiring arrangement according to the invention.

In Figs. 1 and 2, l denotes a rack or frame carrying horizontal crossbars I which serve as support for 10 to 15 selector switches 2 and theirpertaining sets of relays 3. The selector and relay sets or groups areattached to one side of the rack, while the lines 5 which are to beconabove the small boxes in which the electric filters 6 are placed.

The above described arrangement involves the advantage that the highfrequency oscillations may be applied to existing racks or frames and, 5moreover, that the wiring in these racks will become extraordinarilysimple. In addition, each filter device is fixed to its appertaininggroup or set of selectors and relays, an expedient which enablesreliable supervision of the system and a 10 considerably simplifiedwiring between the various elements. I

The Fig. 3, by way of an example, illustrates the simple wiringconditions attained in accordance with the invention. The wires to thecon- 15 tacts t of the cut-oif relay (not shown) which is allotted tothe ore-selector circuits, are connected to the speech wires (12 and D2of the final switch, and to the subscribers line a, bat the terminalstrips of the pre-selector frame. The 20 wires which are extended to thesubscribers line over the main distributor are looped through anexchange filter by a simple wiring change. The lines a, b are associatedwith the output side of the electric filter and the high frequency os-25 cillations are impressedover the conductors al, bl.

What is claimed is:

1. In a telephone exchange system, selector switches arranged in groups,high and low fre- 30 quency separating filters also arranged in groupscorresponding to said selector groups, a plurality of two wire telephonelines arranged in groups corresponding to said switches and filters,each line having a filter associated therewith, a unitary supportingframe having a plurality of racks one for each of said groups ofswitches filters and lines, whereby each filter is mounted immediatelyadjacent the common connections between the associated selectors andlines.

2. In a telephone exchange system, preselector switches arranged inlinear groups, control relays arranged in linear groups corresponding tosaid switches, high and low frequency separating filters arranged inlinear groups corresponding to said switches and relays, a plurality oftwo wire telephone lines arranged in groups corresponding to saidswitches relays and filters, a unitary supporting frame having aplurality of Tacks one for each. group of switches, relays filters andlines, whereby each filter is mounted immediately adjacent thecorresponding switches relays and lines.

3. A telephone exchange system according to claim 2 in which the twoWire lines and associsubscribers lines and through which the subscriberslines are connected to the contacts of the associated cut-off relay,said subscribers lines being connected to the low frequency output endof the associated filter, a high frequency line connected to the inputof each filter, said lines filters relays and selectors being arrangedin corresponding linear groups, and a unitary supporting frame havingsupporting racks for said lines filters relays and switches, wherebyeach filter can be mounted immediately adjacent the associated relaysand pre-selector switches.

ALFRED WIESSNER.

